The present invention relates to apparatus for the separation of liquid mixtures, especially organic substance mixtures and aqueous salt solutions.
Organic mixtures which are in a liquid state at room temperature, especially those which are relatively difficult to separate, advantageously are separated by techniques known as perstraction and pervaporation, in both cases a high degree of separation being realized through the use of permselective (permeability selective) membranes or diaphragms. With perstraction, also referred to as membrane-delayed extraction, the liquid mixture is delivered at high pressure (up to about 1000 atmospheres) to the front face of a microporous, permselective membrane and the permeating material, i.e. the fraction to be separated out in a suitable extraction liquid, is withdrawn at low pressure (for instance 1 atmosphere) from the membrane rear face.
On the other hand, in the case of pervaporation dense or non-porous permselective membranes are used, to the front face of which there is delivered the liquid mixture at atmospheric pressure or low excess pressure and at the rear face of which there is withdrawn the permeating material under vacuum in a vapor state.
The multifarious separation work which is to be carried out at the present time, however, results in very different requirements which are dependent upon numerous parameters with respect to the substance and the operating conditions and are especially difficult to determine by calculations. Therefore for each case special equipment must be constructed, requiring for this purpose a high experimental expenditure before it is possible to devise a separation apparatus which really allows for satisfactory separation operations on a technical scale.